New to thread, bought a g2 and is smoking.....

[OYSIFLY]

Hi all, I have bought a G2 that's in pretty good shape minus the smoking and a little rattle in the clutch. I have two questions:

1) Can I simply replace the piston and rings or should I do valves and rings all at once?

2) the rattle in the clutch looks like 1 fly weight being loose, can I replace just one of the weights?


Or is it better to replace the motor with a clone of some kind? I'm not sure of the HP rating or what motors would work, any help would be appreciated.

Thanks!!!

[toadady]

go ahead and purchase two valves and a valve stem seal, your valves will probably be shot and your seal will be as hard as a rock, and take your block to a machineshop and have them measure it, i bet it will need to be bored, mine wouldn't clean up at .25mm, had to go .50 mm.

yes you can get just one flywheel weight. but i would get them all.

[sho305]

Good answer Toadady. Often the oil ring goes first in these so they run ok but smoke, can be valves too.

I put a clone in, a '16hp' 420cc. Some call them 13hp now some said 15hp. Anyway the thing has super nice power compared to stock, like double the power. It runs about the same RPM with no governor. It will spin up hills and towing things with 22s with large knobs. It goes about 30mph gps just like stock with no governor, but gets there way faster.

The issue is you have to do some fabrication to get it in there. I did use the stock clutch and gen/starter so it is just like stock to drive. Making a mount is easy IMO, you have to plumb the intake and exhaust then make a linkage for the throttle and choke all that is the hard part.

In other words, you have to be up for the project and able to do it. I don't know of any parts made to do it other than the clutch adapter CPP makes.

[OYSIFLY]

Thanks for the fast replies!

That was my next question, I wasn't sure if I need the .25 or the .50 ring kit. When I get it pulled I will find a machine shop and have them check it. I saw one kit that had the sleeve, piston and rings so I thought about going that route. but if I can just go with the piston and ring, I'll get it measured.

And I'll also replace the valves and sleeves.

The engines runs fine and smooth, just looks like I'm fogging the neighborhood. LOL

I paid $200 for the cart so hope I don't get in more then it's worth?

[toadady]

Originally Posted by OYSIFLY

Thanks for the fast replies!

That was my next question, I wasn't sure if I need the .25 or the .50 ring kit. When I get it pulled I will find a machine shop and have them check it. I saw one kit that had the sleeve, piston and rings so I thought about going that route. but if I can just go with the piston and ring, I'll get it measured.

And I'll also replace the valves and sleeves.

I paid $200 for the cart so hope I don't get in more then it's worth?

sleave?? these do not have a removable sleave, post a link to the kit,

[OYSIFLY]

sorry toadady, meant seal. :) my bad

[toadady]

not that it matters, i just got done overhauing mine for the third time,

buy YAMAHA parts, might cost i little more, but quaility is diffrent, i notieced it esp. on the crankcase gasket, it had a bead of silicone where they are prone to leak,

start with one oil and keep it . i switched oil on mine and it trashed the rings, this might be from the chepo rings or a splash lubed motor doesn't like change, duno,

go to the need service manual thread and get a copy of it, these engines are as simple as a Briggs motor,

[smallblock450sl]

I might suggest a compression test first. Remeber to do it at "wide open throttle". That can give you some help decideing what to do after you tear down the engine. You will need to remove the clutch "fixed" sheave and there is a special puller for that, but some have done it without the tool. When takeing the side case off, try to keep the cam and balancer in place and note the timeing marks, or make your own for reassembly. I recommend the compression test because you may only need to hone and rering. I've seen alot of Yamaha's that had bad oil rings. Yes do inspect the head/valves, the head will be off anyway, sometimes a decarbon and lapping compound is all you need. I also recommend new valve stem seals. They only came with one on the intake valve, but the head is machined for seals on both valves. Good luck on your new toy.

[OYSIFLY]

Ok, here's the deal:

This cart sat outside for alittle over a year. Compression test was 190 with throttle open. It's smoking pretty good though. Think the oil ring is stick to the cylinder or could it be something else? With that high of compression I would think the piston and sleeve isnt in bad shape, although I am not a mechanic.

What else do you think?

[smallblock450sl]

Originally Posted by OYSIFLY

Ok, here's the deal:

This cart sat outside for alittle over a year. Compression test was 190 with throttle open. It's smoking pretty good though. Think the oil ring is stick to the cylinder or could it be something else? With that high of compression I would think the piston and sleeve isnt in bad shape, although I am not a mechanic.

What else do you think?

190 lbs is excellant! May just need a hone and a valve job.